【发布时间】：2011-08-22 10:27:42
【问题描述】：
我对 android 开发完全陌生，必须编写一个简单的应用程序来读取大学的 nfc 标签（带有 nexus s）。
我的问题是，当 nexus 发现标签时，我的应用程序未列在“选择操作”-弹出窗口中。目的是使用http://developer.android.com/guide/topics/nfc/index.html 中描述的前台调度方法读取标签 和 http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/nfc/ForegroundDispatch.html
我认为清单中缺少一些东西，但我不知道是什么。 这是清单：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.iforge.android.nfc"
>
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.NFC" />
<uses-permission android:name="android.permission.CALL_PHONE" />
<application
android:icon="@drawable/icon"
android:label="@string/app_name"
>
<activity android:name=".simulator.FakeTagsActivity"
android:theme="@android:style/Theme.NoTitleBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="TagViewer"
android:theme="@android:style/Theme.NoTitleBar"
>
<intent-filter>
<action android:name="android.nfc.action.NDEF_DISCOVERED"/>
<data android:mimeType="mime/type" />
</intent-filter>
<intent-filter>
<action android:name="android.nfc.action.TECH_DISCOVERED"/>
</intent-filter>
<intent-filter>
<action android:name="android.nfc.action.TAG_DISCOVERED"/>
</intent-filter>
</activity>
</application>
<uses-sdk android:minSdkVersion="10" />
<uses-feature android:name="android.hardware.nfc" android:required="true" />
这是发现标签时应调用的活动代码（由 android NFCDemo 和 ForegroundDispatch 示例构建）：
public class TagViewer extends Activity
{
WebView webView;
private NfcAdapter mAdapter;
private PendingIntent mPendingIntent;
private IntentFilter[] mFilters;
private String[][] mTechLists;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
mAdapter = NfcAdapter.getDefaultAdapter(this);
mPendingIntent = PendingIntent.getActivity(
this, 0, new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
IntentFilter ndef = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
try {
ndef.addDataType("*/*"); /* Handles all MIME based dispatches.
You should specify only the ones that you need. */
}
catch (MalformedMimeTypeException e) {
throw new RuntimeException("fail", e);
}
mFilters = new IntentFilter[] {
ndef,
};
mTechLists = new String[][] { new String[] { NfcF.class.getName() } };
setContentView(R.layout.tag_viewer);
webView = (WebView) findViewById(R.id.webView1);
webView.getSettings().setJavaScriptEnabled(true);
webView.getSettings().setJavaScriptCanOpenWindowsAutomatically(false);
webView.getSettings().setPluginsEnabled(false);
webView.getSettings().setSupportMultipleWindows(false);
webView.getSettings().setSupportZoom(false);
webView.setVerticalScrollBarEnabled(false);
webView.setHorizontalScrollBarEnabled(false);
resolveIntent(getIntent());
}
@Override
public void onResume() {
super.onResume();
mAdapter.enableForegroundDispatch(this, mPendingIntent, mFilters, mTechLists);
}
@Override
public void onPause() {
super.onPause();
mAdapter.disableForegroundDispatch(this);
}
void resolveIntent(Intent intent)
{
// Parse the intent
String action = intent.getAction();
if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action))
{
// When a tag is discovered we send it to the service to be save. We
// include a PendingIntent for the service to call back onto. This
// will cause this activity to be restarted with onNewIntent(). At
// that time we read it from the database and view it.
Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
NdefMessage[] msgs;
if (rawMsgs != null)
{
msgs = new NdefMessage[rawMsgs.length];
for (int i = 0; i < rawMsgs.length; i++)
{
msgs[i] = (NdefMessage) rawMsgs[i];
}
}
else
{
// Unknown tag type
byte[] empty = new byte[] {};
NdefRecord record = new NdefRecord(NdefRecord.TNF_UNKNOWN, empty, empty, empty);
NdefMessage msg = new NdefMessage(new NdefRecord[] {record});
msgs = new NdefMessage[] {msg};
}
// Setup the web-view
setUpWebView(msgs);
}
else
{
Log.e("ViewTag", "Unknown intent " + intent);
finish();
return;
}
}
void setUpWebView(NdefMessage[] msgs)
{
if (msgs == null || msgs.length == 0) return;
String urlToLoad = MessageParser.parseMessage(msgs[0]);
if(!urlToLoad.matches("")) webView.loadUrl(urlToLoad);
}
@Override
public void onNewIntent(Intent intent)
{
setIntent(intent);
resolveIntent(intent);
Log.i("Foreground dispatch", "Discovered tag with intent: " + intent);
}
}
我尝试了很多，但没有任何效果。如果有人能告诉我我错过了什么，那就太好了。我没时间了:-(
请
谢谢
【问题讨论】：
标签： android nfc foreground dispatch